The filling and sealing of containers on a high volume basis generally requires fairly sophisticated equipment and several patents have issued in recent years on machines for this purpose. In the specific field of bag packaging, U.S. Pat. Nos. 2,877,609; 2,923,111; 3,269,278; 3,381,446; 3,462,913; and 3,492,783 are typical of patents disclosing machines and methods for filling and sealing bags on a high volume basis.
In each of the above noted patents a web of flexible packaging material, commonly a thermoplastic material, is folded longitudinally and provided with spaced, transverse sealing lines, typically heat seal lines, to divide the web into a series of interconnected compartments which are thereafter filled with the desired product and their open ends sealed, again, usually by means of a heat seal.
In some of these disclosures, for example U.S. Pat. No. 3,492,783, the transverse seal lines extend from the bottom edge to a point short of the top edge to provide a pair of continuous free edges, apparently to permit the upper edges to be spread by a plow-like member to facilitate insertion of a filling nozzle into each of the compartments.
While each of the systems disclosed in the above noted patents would appear to offer advantages over a manual packaging operation, it will be apparent that such systems are necessarily rather complicated since they require fairly precise indexing of the filling mechanisms with the remaining components of the apparatus. Additionally, where sterile packaging is required, it will be apparent that sterile packaging will be difficult, if not, as a practical matter, impossible, to attain where the bags are formed initially from an open web which is thereafter folded and sealed.
Where the product being packaged is a fluent one, such as, but not necessarily, a liquid, metering of the correct amount of the product into the packages will obviously present technical problems which must be resolved to create a successful system. Further, if a package is accidentally overfilled, it will be seen that spillage may result requiring termination of the packaging operation to permit cleaning the apparatus.